本报警器采用电桥工作原理,具有警戒线断路和短路都报警功能,并且一旦报警,即使将警戒线复原,报警声也不停止。电路及其工作原理本报警器电路如图所示。分为发声电路和触发控制电路两部分。 1.发声电路:本报警器发声电路采用报警器专用集成电路KD9561,和普通的音乐集成电路一样,它需外接一个振荡电阻和放大三极管,以推动扬声器工作。它有两个触发端,触发端接 The alarm uses the bridge working principle, with alarm line open circuit and short circuit alarm function, and once the alarm, even if the cordon recovery, alarm sound does not stop. Circuit and its working principle The alarm circuit as shown. Divided into voice circuit and trigger control circuit in two parts. 1. Audible circuit: The alarm sound circuit using alarm ASIC KD9561, and ordinary music integrated circuit, it needs an external oscillation resistor and amplification transistor to promote the speaker. It has two trigger terminals that trigger the termination